Snow Mold Disease Control on Creeping Bentgrass November 2003 - May 2004
Eleven chemical and control treatments were evaluated on a 102-year-old sward of creeping bentgrass in southern Ontario during November 2003 to May 2004 for grey and pink snow mold control. Separate sets of plots were inoculated with Typhula incarnata or Typhula ishikariensis for grey snow mold, or Microdochium nivale for pink snow mold. The fungicides tested included: Quintozene (250 g /100 m2), which is registered and recommended for controlling snow mold diseases of turfgrass in Ontario, plus nine other treatments involving chemicals provided by Syngenta for grey and pink snow mold control. All treatments were applied 26 November 2003 over bare ground. Inoculum was applied on 28 November 2003. Biotic plus abiotic injury was assessed as winter injury weekly from 25 March (snowmelt) until 7 May (greenup). After snowmelt and at greenup, Daconil 2787 + Medallion (103 ml + 15 g/100 m2 ), Banner Maxx + Medallion (103 ml + 15 g/100 m2), and Banner Maxx + Daconil 2787 (103 ml + 240 ml/100 m2), all provided excellent results with significant suppression of both snow molds, and overall winter injury less than 10% area affected. Daconil 2787 (500 ml/100m2) showed excellent suppression at both snowmelt and greenup except for non- significant suppression of winter injury on plots inoculated with Typhula incarnata. Medallion (15 g/100 m2) provided excellent results at greenup for both snow molds; at snowmelt, there was significant winter injury suppression on plots inoculated with Microdchium nivale or Typhula ishikariensis, but not Typhula incarnata. Daconil 2787 (240 ml/100 m2) showed very good results for pink snow mold control, but the winter injury on grey snow mold plots was not significantly different than the inoculated control. Banner Maxx (206 ml/100 m2) also provided excellent suppression except on plots inoculated with Typhula ishikariensis. Banner Maxx (103mL/100m2) did not show any significant suppression at snowmelt, but by greenup, the plots inoculated with Microdochium nivale or Typhula incarnata were had significantly less injury than the inoculated control.. Quintozene (250 g/100 m2) also provided good results with the exception Typhula ishikariensis plots at snow melt. Attempts to isolate the inoculated pathogen species from injured grass in each inoculated control plot were successful except for one block inoculated with Typhula ishikariensis, demonstrating the presence of the inoculated pathogens. Winter injury results for 25 March and 7 May 2004, plus pathogen isolation results are presented.